Expansion plate



Sept. 2 1967 Filed y 5, 1964 K. s. SVENDSEN EXPANSION PLATE 5 heets- 1 l p 1967 K. s. SVE NDSEN 3,343,327 EXPANSION PLATE Filed May 5, 1964 5 Sheets$heet 2 F'IG 2 F'IG 4 Sept. 26, 1967 K. s. SVENDSEN EXPANSION PLATE 5 Sheets-Sheet 3 Filed May 5, 1964 United States Patent O 3,343,327 EXPANSION PLATE Konrad S. Svendsen, Bloomfield, Conn., assignor to Combustion Engineering, Inc., Windsor, Conn., a corporation of Delaware Filed May 5, 1964, Ser. No. 365,075 9 Claims. (Cl. 52-573) This invention relates to an expansion joint and more particularly to an airtight connection between two adjacent members subject todifferent operating temperatures and hence to different changes in-physical dimensions.

An object of this invention is a fluid-tight connection between two adjacent members or surfaces by means of which one member may expand or move relative to the other while maintaining the fluid tight connection.

A further object is a distortable plate or sheet welded to adjacent members to provide a fluid-tight connection between the members and distorta-ble to accommodate different expansion of the members.

Further objects and advantages will be apparent from the following specification and the attached drawings in which:

FIG. 1 is a schematic outline of a steam generator and furnace in which this invention finds particular application;

FIG. 2 is a detailed cross section on line 22 of FIG. 7 of the cupped plate panel connection incorporating the invention and its attachment to adjacent members;

FIG. 3 is a detailed cross section on line 3-3 of FIG. 7 of the panel comprising a cupped sheet and a plain sheet;

FIG. 4 is a detail of the corner construction;

FIG. 5 is a perspective view of an individual cup;

FIG. 6 is a partial view of an assembled sheet or plate;

FIG. 7 is a side view of an assembled wall comprising panels of plates connecting a steam header and an ash hopper of a steam generator;

FIG. 8 is an enlarged top view, somewhat exaggerated, of a portion of a distorted sheet;

FIG. 9 is an enlarged side view somewhat exaggerated of a corner of a distorted wall; and

FIG. 10 is an enlarged top view of the corner shown in FIG. 9.

A problem has existed in providing a fluid-tight connection between two adjacent members subject to different operating temperatures and hence to different amounts of expansion, particularly where it is impractical to use slip joints or packings. This problem is particularly acute in large vapor generators in which there may be temperature differences of several hundred degrees Fahrenheit between adjacent surfaces, such as between adjacent water walls or tube and steam walls or tubes or between a steam header or ring and an adjacent uncooled ash hopper through which combustion gases are directed. Because of the large size of the steam generators now being considered, and the high temperatures at which they operate, the difference in expansion between adjacent surfaces may cause one surface to lengthen appreciably more than the adjacent surface or element.

The present invention provides a structure which will produce such an air-tight connection and accommodate the relative elongation or expansion of two adjacent elements under the severe elevated temperature conditions of the present day steam generator.

A typical steam generator is diagrammatically illustrated in FIG. 1 to show one application of the invention and comprises a furnace 10 having a combustion chamber 12 defined by parallel vertically extended welded together tubes 16 forming the furnace walls and a portion Patented Sept. 26, 1967 of the gas pass 36 and adapted to have water forced therethrough for conversion into steam. The water is fed by feedwater pumps, not shown, into headers such as 18, 20 and 22 and forced upward through the tubes 16 into a header 24 and thence into a steam drum 26 in a well-known manner. Steam is separated from the water in the drum 26 and is led through the pipes 28 to the header 30 and tubes 32 to a header 34 from which it may be fed to additional superheaters, not shown, and thence to the point of consumption, not shown. It will be noted that the gases from the combustion chamber 12 pass upward and then laterally through a horizontal gas pass indicated generally at 36 thence through a downwardly directed gas pass 38 into a soot hopper 40 and out through a duct 42 to the usual stack.

The tubes 16 and 32 in the gas pass 36 are subject to a materially different operating temperature because the tubes 16 are generally water cooled while the tubes 32 are generally steam cooled with the steam being at a materially higher temperature than the water. Hence, the adjacent tubes 16 and 32 are subject to different amounts of expansion. It is necessary that the gas pass and in fact the entire furnace from combustion chamber to stack be maintained as an air-tight duct particularly where the furnace and combustion chamber is operated at an elevated pressure or pressurized. It is therefore necessary to keep the joint or connection between the tubes 16 and the tubes 32 which form the walls of the duct forming gas pass 36, air-tight.

Another point that must be kept air-tight is the connection between the steam header 34 and the walls of the ash hopper 40. The header 34 is steam cooled while the walls of the ash hopper are subjected to the full temperature of the combustion gases passing through the hopper on the way to the stack and hence are raised to a temperature somewhat higher than the steam cooled header 34.

In furnace construction it is usual to suspend the entire furnace including all of the walls from overhead as by beams 44 and rods 46 supporting the header 30 and the tubes connected therewith. By this type of construction adjacent tubes 16 and 32 will be maintained substantially relatively stationary with respect to each other near the point of suspension, i.e., near the headers from which they are suspended, while the lower ends of the tubes 16 and 32 will be subject to considerable relative longitudinal movement as the tubes 32 expand more than the tubes 16.

As will be explained in more detail later, the walls of the ash hopper 40 are suspended from the header 34 and being subject to a higher operating temperature than the header 34 will expand to make the perimeter of the ash hopper considerably greater than the perimeter of the header 34. Applicants expansion plate is used to connect and form an air-tight connection between the header 34 and the walls of the hopper 40 and is shown somewhat schematically and diagrammatically at 48 in FIG. 1. A similar construction is also used to connect and form an air-tight connection between adjacent groups of tubes 16 and 32 and is shown diagrammatically at 50.

In order to more fully explain the invention the details of the structure at 48 connecting the header 34 with the walls of the hopper 40 are illustrated and explained. This explanation will make it adequately clear how this construction can 'be used to connect adjacent surfaces such as the tubes 16 and 32 and it is believed unnecessary to illustrate that detailed construction.

FIG. 2 shows a section of the header 34 and a wall 52 of the hopper 40. The wall 52 is secured in any suitable manner, as by welding, to a channel iron 54 which is suspended from the header 34 by straps 56 and pin joints 58. The upper edge of wall 52 is received between and forms a slip joint with a pair of spaced plates 60 secured in any suitable manner, as by welding, to the header 34. A plate indicated generally at 62 and forming the subject of this invention is positioned outside of the hopper 40 and has one longitudinal edge secured in any suitable manner as by welding to the header 34 and the opposite longitudinal edge secured in any suitable manner, preferably by welding, to the channel 54 supporting the hopper walls.

The Walls formed by plates 62 extend around the four sides of the rectangular hopper 40 and forms an air-tight connection between the hopper and the header 34. It will be appreciated that the tubes leading vertically upward from the header 34 are welded together to form the duct defining the gas pass 38 or other suitable means are provided to define that gas pass terminating in the header 34.

FIG. 7 is a side view of one half of the ash hopper which may be seventy or more feet across and shows one half of the plate 62 extending along that side with the center line of the plate shown at the extreme left-hand edge of the figure being taken as a portion of the hopper that has no relative longitudinal movement with respect to the header 34 so that the hopper is substantially fixed longitudinally of the header 34 at this point but expands so as to move longitudinally outward of the header 34 at the corner of the hopper. Hence all four corners of the hopper will move outwardly with respect to the rectangular header 34.

It will be noted that the plate 62 is made up of a plurality of individual panels such as 64, 68 and 70 among others. These panels are arranged in a row with their adjacent edges secured together and together form the plate 62. As there is substantially no relative movement of the hopper wall longitudinally of the pipe forming the header 34 adjacent the center line of the hopper side wall, the panel 64 is a plain, rigid sheet having one edge welded to the header 34 and the other edge welded to the channel iron 54.

At the end of the plate 62, however, increasing relative longitudinal movement must be accommodated so that the panel 70 which will be described in more detail hereinafter is constructed to permit such relative movement by allowing the sheet forming the panel 70 to torsionally distort under shear forces to accommodate such relative movement. A partial view of the torsionally distorted sheet, with the distortion somewhat exaggerated to more clearly illustrate the same, is shown in FIG. 9. The relative longitudinal movement of header 34 and channel 54 produces a force longitudinally of one edge of the plate 62 and a parallel force in the opposite direction longitudinally of the opposite edge of the plate 62. The spaced apart non-intersecting forces produce a force couple which is absorbed by shear deformation of the plate 62.

It will be appreciated that as the header 34, the wall to the hopper 40 and the plate 62 are secured together against relative longitudinal movement at the center line, all of the relative longitudinal expansion between the walls of the hopper 40 and the header 34 will appear at the end of the plate 62 and must be accommodated by the sheet 70. At the intermediate panels, of which seven are shown in FIG. 7, between the panels 64 and the panel 70, increasing amounts of longitudinal movement must be accommodated beginning with a small amount of longitudinal movement in the panel 72 welded to the panel 64 to almost as much movement in the panel 74 as is accommodated by the panel 70 which is welded to the panel 74. The intermediate panels are, therefore, composite panels made up, as in panel 72 (shown in cross section in FIG. 3), of a rigid sheet 76 edge-welded to a flexible or distortable sheet 77 to form the panel 72. The proportion of flexible sheet to rigid sheet being greater, the nearer that panel is to the end of the plate 62 which must accommodate the relative movement, i.e., from the center of the plate to the end of the plate the number of cups in individual panels gradually increases from zero in the center panel until the last panel is entirely cups.

The flexible or distortable sheets 77 are sheets having cup-like depressions in one face of the sheet leaving only a minor portion of the sheet connecting the rims of the cup-like depressed portions. In the now preferred embodiment the sheet is fabricated by forming a substantially square cup as shown in FIG. 5 of sheet metal having a substantially square bottom 78 with tapered upstanding sides 80 terminating in a narrow out-turned flange 82 forming the rim of the cup-shaped member indicated generally at 84. The member 84 may be fabricated either by stamping or welding. A plurality of these cups are arranged side-by-side, 48 of them as shown in panel 70, and their adjacent rims are then welded together to form the flexible sheet. The welded rims form longitudinally and transversely extending continuous ribs arranged at substantially right angles and will hold the sheet against expanding or contracting under the influence of opposed forces applied to opposite ends of a rib and directed longitudinally of the rib normal to the edges of the sheet in the plane of the sheet. The ribs are however transversely flexible. The amount of longitudinal expansion of channel 54 and the extent of the shear deformation under the force couple that can be accommodated is determined generally by the number of cups utilized in forming the sheet, the panel 68 being half-way between the center line and the end of the plate 62, having only half the number of cups as the sheet 70.

A metal strip 86, FIGS. 2, 3 and 4, having a slight in-turned flange 88 along one edge is placed along the outside of the assembled cups forming the flexible sheet and the flange 88 is welded to the flanges 82 forming the outside edge of the sheet. The strip 86 has approximately the same width as the height of the cup 84 and serves as a means for fastening the flexible sheet to adjacent sheets of panels or to the elements to be connected by the sheets or panels such as the header 34 and the channel iron 54. Relative longitudinal movement of header 34 and channel iron 54 and the forces forming the force couple incident to such movement are transmitted longitudinally of the strips 86 to the longitudinal edges of their associated panel. As seen in FIG. 2 the edge of the strip 86 opposite its flange 88 is secured preferably by welding to an angle iron 90 which in turn is welded to the header 34 thus securing one edge of the sheet to the header 34. At the opposite edge of the sheet 77 the edge of the strip 86 opposite its flange 88 is secured to a U-shaped sheet metal strip 92, preferably by welding, which in turn is secured, also preferably by welding, to the channel 54 thus securing the flexible sheet in airtight relation to the header 34 and the channel 54 and forming an air-tight connection therebetween.

In order to prevent bulging of the flexible sheet such as that forming the panel 70 from the pressure inside the hopper, a channel iron 94 is supported against the outside of the bottoms 78 of the cups 84 by means of an angle clip 96 welded to the angle iron 90 at one end of the channel 94 and an angle clip 98 welded to the channel 54 at the other end of the channel 94. Where a plain sheet such as 76 in FIG. 3 is used to form either an entire panel or a portion of a composite panel the flange of a strip 86 is welded to the outside edges of the sheet 76 so as to form a depending flange for the sheet of approximately the same height as the depth of the cups 84 and this strip 86 is secured in the same manner as that described for the flexible sheet to the angle iron 90 or the U-shaped strip 92 or the edge of the strip 86 of an adjacent sheet 77 or panel. Bulging of the sheet 76 in panels 64 and 72 from the pressure in the hopper is prevented by means of a channel 102, FIG. 3, secured between the plate 76 and the supporting channel 94.

Where the plates 62 meet to form a corner such as the corner of the hopper the flanged strips 86 forming the outside edge of the corner panels are connecetd by a V- shaped strip 104 to close the joint. If necessary a closure element may be welded between the strip 104 and the strips 86 to close any gaps between the strips and the angle iron 90 and a closure plate 106, FIGS. 9 and 10, may be welded between the angle 90 and the header 34 to complete the air-tight closure of the corner.

FIGS. 8, 9 and show, somewhat exaggerated, how the flexible plate distorts to accommodate the difference in longitudinal expansion of the elements it connects. From FIGS. 8 and 9 it will be seen that the bottom 78 of the cup is partially rotated but remains substantially undistorted and that the distortion takes place in the walls 80 of the cup which are warped, the flexible flangededges of which are skewed and warped and take on a somewhat Wavy appearance. The transversely extending ribs formed by the welded rims are forced into an oblique position with respect to the longitudinally extending ribs. The strips 86 which in effect form a flange depending from the rims of the outside cups of an assembled flexible sheet, transmit the longitudinal movement and forces, which are in effect a force couple, to the sheet and absorb any distortion of those rims by having the edge of the strip 86 adjacent the rims take on the distorted shape of the rims while the opposite edge of the strip 86 being welded to the angle iron 90 or the U-shaped strip 92 remains substantially undistorted. As shown in FIGS. 9 and 10 the hopper wall 52 expanding longitudinally more than the rectangular header 34 and being held against relative longitudinal movement at the centers of the walls, forces the corners of the hopper radially outward with respect to the rectangular header 34. The longitudinal movement of this expansion is absorbed by the longitudinal movement of one edge of the flexible sheet relative to the other under the sheer forces imposed by the expansion and the transverse movement due to this expansion is absorbed by transverse movement of the strip 86 and the U-shaped strip 92. Any differential transverse expansion between the supporting straps 56 and the connecting plate 62 is also absorbed by the strips 86 and the U-shaped member 92.

While for purposes of illustration and explanation the connecting plate has been described in detail as the connection between a steam header and an ash hopper subject to different operating temperatures and hence to different amounts of expansion. It will be understood that the invention is not limited to such structure, however, and that this invention may be used as a means for connecting other elements subject to'limited relative movement particularly where that relative movement is occasioned by temperature differences and it is desired to have the connection form a air-tight connection between the two elements.

One example would be a plate such as indicated in 50 in FIG. 1 which may be used to connect adjacent water wall tubes 16 and steam cooled tubes 32 adjacent thereto. In such as case an angle iron such as 90 or even a straight bar is welded to a selected one of the tubes 16 and a selected one of the tubes 32 and the strip 86 is welded to that angle iron or bar. The top end of the plate may be closed by a scalloped strip fitting over the intermediate tubes and the expansion plate may extend across the furnace and up the other side to complete the air-tight connection. The fourth side of the connection is formed by the roof of the furnace.

As an example of proportions it has been found that a plate comprising 48 cups arranged six transversely of the plate and eight longitudinally of the plate to form the end panel of the plate and comprising cups approximately 4" deep and 6" square at the top edge and 5" square at the bottom and made of fourteen gauge sheet steel can safely absorb a relative longitudinal movement of approximately 1 /2" longitudinally of the edges formed by the eight cups. The depending sheets bounding the plates and the U- shaped member may be made of twelve gauge sheet steel.

I claim:

1. Means forming an air-tight connection between two adjacent sections of a gas pass wall, which sections have different relative operating temperatures comprising an elongated imperforate plate edge welded air-tight to and connecting said sections and forming a portion of said wall, said plate comprising a series of transversely extending panels edge welded in side-by-side arrangement, the panel at a selected longitudinal portion of said plate comprising a substantially undistortable plain sheet, the panel at one end of said plate spaced from said selected portion comprising a plurality of cup-shaped elements arranged side-by-side with the rims of adjacent cups connected to form an integral sheet, and the panels between said selected portion and said end comprising a flat plain sheet joined in said-by-side relation to a sheet formed of cupshaped elements, to form a composite sheet, the proportion of the composite sheet formed by the cup-shaped members being greater in the panels near said end than in the panels near said selected portion.

2. Means connecting, closing the space between, and forming an elongated joint between, adjacent separated portions of a wall, said portions being subject to relative movement longitudinally of said joint, said connecting means comprising a plate formed of at least one sheet having a plurality of cups arranged side-by-side, so as to absorb a force couple produced by said relative longitudinal movement, each cup having upstanding sides and a rim, said cups connected at their rim edges by connections which are narrow with respect to the depth of the cup, said rims being connected along opposite edges of the plate to the respective adjacent wall portion, said relative longitudinal movement of said portions and the resulting force couple being accommodated by shear deformation of said plate, causing skewing of said rims and warping of said upstanding sides.

3. Means as claimed in claim 2 including means connected with said wall portions and extending across the bottoms of said cups for supporting said plate against a pressure difference on opposite sides of said'wall.

4. Means as claimed in claim 2 including a flange depending from said plate and welded to said wall and forming the connection between the edges of the plate and the wall portion, said flange absorbing transverse forces and movement of said wall by bending of said flange and transmitting the shear forces from said wall to said plate.

5. Means as claimed in claim 4 in which the plate comprises a plurality of rectangular cupped sheets arranged side by side, each sheet having a deformable flange depending from the four sides of the sheet with adjacent sheets connected through adjacent flanges.

6. Means as claimed in claim 2 in which said connections form intersecting continuous ribs extending the length and width of said plate.

7. An air-tight connection connecting adjacent walls of two abutting ducts, said ducts having adjacent'edges subject to relative movement longitudinally of said edges and producing a change in the relative perimeter of said abutting ducts, said connection comprising an imperforate sheet having a series of cup-shaped rectilinear depressions in one side and connections which are narrow with respect to the depth of the depressions directly connecting the rims of adjacent depressions, said narrow connections forming one set of continuous ribs extending lengthwise of said sheet and another set extending substantially at right angles thereto transversely across said sheet, means connecting one edge of said sheet in an air-tight manner with one wall of one duct to form an integral extension of said duct Wall and to apply forces in one direction longitudinally of said edge, and means connecting the opposite edge of said sheet in an air-tight manner with the adjacent wall of the other duct to form an integral extension of said adjacent wall and to apply forces in the opposite direction lengthwise of said opposite edge, said sheet being distortable by said forces and the relative longitudinal movement of said adjacent edges, said connection accommodating said relative movements of said adjacent duct walls by shear distortion of said sheet including positioning said transversely extending ribs obliquely to said longitudinally extending ribs.

8. In combination with two adjacent members subject to temperature destructive of organic material and spaced to form a longitudinally extending gap therebetween and subject to relative movement longitudinally of said gap, a metal plate having one edge secured along and movable with one member and having the opposite edge secured along and movable with the other member and providing a sealed closure closing said gap, said plate having means accommodating said relative movement by shear deformation of said plate, said means including a sheet having a plurality of rectilinear depressions in one side, over substantially the entire area of said sheet so as to absorb a force couple produced by said relative longitudinal movement, each depression comprising an individual cup-shaped element having a bottom and warpable upstanding sides terminating in a rectilinear rim directly connected to the rim of each adjacent element, the connected rims forming ribs extending across said sheet and bendable in the plane of, and transverse to the plane of, said sheet, the rim portion on opposite sides of each depression movable longitudinally in opposite parallel directions by said relative movement and said force couple, saidmovement causing skewing of said rim, warping of said upstanding sides and partial rotating of the bottom of each element and means connected with said members and extending across the bottoms of said cup-shaped elements for supporting said sheet against movement normal to the plane of said sheet.

9. A torsionally distortable panel for connecting two adjacent members, which members are subject to movement longitudinally of the panel edge, said panel ineluding a sheet comprising a plurality of rectilinear cupshaped elements arranged side-by-side so as to provide for torsional distortion of said sheet and to absorb a force couple produced by said longitudinal movement, each element having a rim, means directly connecting adjacent rims to form an integral cupped sheet, said connected rims forming intersecting continuous ribs extending from edge to edge across said sheet, means connected with the rims forming one edge of said sheet for connecting said one edge with one member and means connected with the rims forming the opposite edge of said sheet for connecting said opposite edge with the other member, said edge connecting means adapted to transmit the relative longitudinal movement of said members, and the resulting force couple, longitudinally to the opposite edges of said sheet, said sheet being deformable by said transmitted relative longitudinal movement, causing skewing of said rims, bending of said ribs and changing of the angular relation of intersecting ribs.

References Cited UNITED STATES PATENTS 1,605,513 2/1926 Connery 52573 2,329,789 9/1943 Schank et a1.

2,466,859 4/1949 Northup 29-180 X 2,876,927 3/1959 Henning 52573 X 3,215,301 11/1965 Armstrong 52573 X 3,279,973 10/1966 Arne 52573 DAVID J. WILLIAMOWSKY, Primary Examiner.

HARRISON R. MOSELEY, Examiner.

D. L. TAYLOR, Assistant Examiner. 

2. MEANS CONNECTING, CLOSING THE SPACE BETWEEN, AND FORMING AN ELONGATED JOINT BETWEEN, ADJACENT SEPARATED PORTIONS OF A WALL, SAID PORTIONS BEING SUBJECT TO RELATIVE MOVEMENT LONGITUDINALLY OF SAID JOINT, SAID CONNECTING MEANS COMPRISING A PLATE FORMED OF AT LEAST ONE SHEET HAVING A PLURALITY OF CUPS ARRANGED SIDE-BY-SIDE, SO AS TO ABSORB A FORCE COUPLE PRODUCED BY SAID RELATIVE LONGITUDINAL MOVEMENT, EACH CUP HAVING UPSTANDING SIDES AND A RIM, SAID CUPS CONNECTED AT THEIR RIM EDGES BY CONNECTIONS WHICH ARE NARROW WITH RESPECT TO THE DEPTH OF THE CUP, SAID RIMS BEING CONNECTED ALONG OPPOSITE EDGES OF THE PLATE TO THE RESPECTIVE ADJACENT WALL PORTION, SAID RELATIVE LONGITUDINAL MOVEMENT OF SAID PORTIONS AND THE RESULTING FORCE COUPLE BEING ACCOMMODATED BY SHEAR DEFORMATION OF SAID PLATE, CAUSING SKEWING OF SAID RIMS AND WARPING OF SAID UPSTANDING SIDES. 